Under normal operating and storage conditions, lubricants are subject to high temperatures and oxygen which leads to oxidation and decomposition of the lubricant. Oxidation of a lubricant can lead to the build-up of oil-soluble acids, lacquers and sludge which cause serious damage to engines and other lubricated systems. Typically, antioxidant additives are blended with lubricants in order to improve the stability of the lubricant and thereby enhance the ability of the oil to resist oxidation.
Additionally, mechanical systems under heavy loads will deteriorate due to the frictional forces created by relatively moving and bearing metal surfaces. Often, lubricants for such operations cannot prevent wear of the metal and as a result the performance of the system is adversely affected. Often, antiwear additives are blended with lubricants in order to prevent wear and increase the operating life of the systems.
The reaction products of preformed Mannich bases and dithiophosphoric acids having at least one reactive hydrogen have been described as antioxidants and antiwear additives in lubricants, fuels and plastics in U.S. Pat. No. 4,806,130.